Choose the number of the sentence that expresses the main idea of the selection

(1) Less than a hundred years ago, many people saw adolescence as a time of great instability and strong emotions. (2) For example, G. Stanley Hall, one of the first developmental psychologists, portrayed adolescence as a period of “storm and stress,” fraught with suffering, passion, and rebelliousness. (3) Recent research, however, suggests that the “storm and stress” view greatly exaggerates the experience of most teenagers. (4) The great majority of adolescents do not describe their lives as filled with turmoil and chaos. (5) Most adolescents manage to keep stress in check, experience very little disruption in their everyday lives, and generally develop more positively than is commonly believed. (6) For instance, a cross-cultural study that sampled adolescents from ten countries, including the United States, found that over 75 percent of them had healthy self-images, were generally happy, and valued the time they spent at school and work.